Hi and WELCOME to YT
! Your Monte sounds just precious, and very, very loved. What was the vet's prognosis, long term, did he/she say? Did the vet recommend seeing a cardiologist or does he/she think Monte's case is simple enough to be managed by a generalist? You always have the option of seeing a cardio. It sounds like your vet doesn't think his heart issues are terribly advanced, given he only prescribed a mild diuretic to take some volume load off of the heart. Otherwise, if his issues advance/worsen, there are other more specific heart meds that could help, lots of options.